1. Field of the Invention
The present invention relates to a rare earth element contained substrate, for a heat generating device, and more particularly, to a substrate for the heat generating device, where the substrate contains the rare earth elements, compounds of rare earth elements, or rare earth on minerals so as to heighten its withstanding temperature and improve its heat dissipation, and being capable of radiating a far infrared ray and yielding negative ions for purifying the air.
2.Description of the Prior Art
As it is well known, a conventional electrical heating device is usually made of a metallic wire, metallic bar, or metallic plate with substantially high resistance; sometime it is formed into a tubular heat generating device containing an electrical heater wire in it.
No matter what the heat generating element is made of a metallic wire (electrical heater wire) a metallic bar (electrical heater bar), a metallic plate (electrical heater plate), or an electrical heater tube, it has the following noticeable defects:                1. The heat generating device made of the aforesaid elements has several common disadvantages that it radiates a harmful electromagnetic wave, and produces useless light energy loss when carrying a current.        2. Being made of resistant material the aforesaid elements generate available heat when carrying a current. However, it is problematic as to how to precisely estimate the obtainable heat energy from a given element of a predeterminded size such as length and cross section because all of the aforesaid heat generating elements have indefinite properties difficult to figure out.        3. With the unsolved problems discussed above, the conventional electrical heating devices are definitely not qualified for use in nowadays high technical electronic industry.        
For improving the noticeable defeats on the prior art, the inventor has dedicated great efforts for years and has applied patents for invention or new models to the intellectual property office in Taiwan, for example: “Electrical Heater Film” (Taiwan Pat. App. No. 93114226) “Electrical Heater Film as Heating Device” (Taiwan Pat. App. No. 93214315), and “Uniform Temperature Heat Conducting Surface Board” (Taiwan Pat. App. No. 93215909).
In the above mentioned electrical heating devices the electrical heater film is made of semiconductor material and is fabricated according to the fabrication process of a semiconductor device. In order to avoid degrading the heat production efficiency, occurrence of an electric shock or radiation of harmful electromagnetic wave when carrying a current, the inventor has provided a ceramic substrate. Notwithstanding its excellent heat energy preservation effect, the ceramic substrate is fragile and frangible, and from a certain angle of view, it is noticeable for poor heat dissipation. The continuation of the research in this respect has finally brought up the inventor to come up with the present invention.